The invention relates to electric connectors, and more specifically, to a connector for connecting contact pins and insulation coated wires to be fitted within a connector housing by pressing the contact pins against the insulation coated wires to break coating of the insulation coated wires so as to bring the contact pin into contact with a core wire without a special pressing tool, that is, to a connector equipped with the so-called piercing type contact pins.
Connectors equipped with the so-called piercing type contact pins have been developed and manufactured which are designed to connect contact pins and insulation coated wires to be fitted within a connector housing by pressing the insulation coated wires against the contact pins to break coating of the insulation coated wires so as to bring the contact pin into contact with the core wire without a specific pressing tool. Such a connector is disclosed in patent documents or the like, such as, for example, JP-A-2002-175845.
FIGS. 12 and 13 illustrate a connector disclosed in the above-mentioned patent document, in which FIG. 12A is a plain view of the connector, FIG. 12B is a cross-sectional view taken as a line XIIB-XIIB of FIG. 12A, FIG. 13A is a cross-sectional view taken as a line XIIIA-XIIIA of FIG. 12A, and FIG. 13B is a perspective view of a contact pin fitted to the connector.
The connector 30 as disclosed in the above patent document, as shown in FIG. 12, includes a plurality of contact pins 34, a connector housing 31 having a rectangular recess 32 on its upper wall, for receiving these contact pins 34 therein, and a cover housing 33 for holding a plurality of insulation coated wires, and which is inserted into the recess 32 of the housing. The contact pin 34 includes a base 35, a protruding tongue piece 36 protruded upward from the base 35, a contact part 37 provided at a front part of the base 35, and a wire locking part 38 standing vertically at a back part of the base 35 as shown in FIG. 13B. The tongue piece 36 has two separated sharp protrusions 36a formed on its tip end, which are designed to break the outer coating of the insulation coated wire (hereinafter referred to as a wire) so as to be brought into contact with a core wire. The wire locking part 38 has two locking pieces 38a, between which a wire W is sandwiched to be prevented from moving around as shown in FIG. 13A.
Connecting the contact pin 34 and the wire W involves inserting a plurality of wires into the cover housing 33 from circular holes disposed at the back part of the cover housing, holding the tip ends of the wires by a clip 39, and pushing the cover housing 33 into the recess 32. That is, pushing the cover housing causes each protrusion 36a of the protruding tongue piece 36 of the contact pin 34 to break the outer coating of the insulation coated wire W and enter into the core wire, thereby electrically connecting the contact pin 34 and the core wire of the wire. A connector with such a structure is also disclosed in JP-A-61-133584.
In the connectors as disclosed in the above prior art, by pushing the cover housing holding the plurality of wires into the recess of the connector housing, the protruding tongue pieces of the contact pins arranged in the recess of the connector housing are plunged into the insulation coated wires, causing the tongue piece to be brought into contact with the core wire of the wire. This allows the contact pins to be connected to the wire without using the specific pressing tool. In this connector, however, the wires are directly connected and fixed to the contact pins, and hence the wires and the contact pins are limited to the specific ones. Any selection and modification of these components cannot be carried out. For example, any one of wires with various sizes and any one of various types of connectors cannot be combined into and connected to each other, which disadvantageously results in a limited design for the connector. That is, the known connector employs only the contact pin that is appropriate for a certain size of the wire. For example, for a small-sized wire, only a contact pin having a wire connection part appropriate for the small-sized wire can be used. For a large-sized wire, only a contact pin having a wire connection part appropriate for the large-sized wire can be used. The combination of the contact pin and the size of the wire is limited, resulting in a small range of the connector design.
Further, in this connector, since one wire is connected to one contact pin, the relative number of wires and contact pins cannot be changed for connection. For example, by changing the numerical relationship between the wires and contact pins, a signal or electric power passing through one wire cannot be divided into a plurality of contact pins, or signals from a plurality of wires cannot be combined into one on the contact pin side.
Further, the known connector makes it difficult to have a structure with good resistance to water. That is, in this connector, the insulation coated wire is plunged into the protruding tongue piece of the contact pin by pushing the cover housing equipped with the wires into the recess of the connector housing. Since the wire is moved together with the cover housing, it is difficult to seal in a waterproof manner the cover housing and the wire, especially an outer periphery of the moving wire. Water may enter into between the recess of the connector housing and the cover housing, thus entering a connection part between the contact pin and the wire.